2014 Kenworth W900 Serpentine Belt Routing & Part Numbers

Quick Answer

• Belt Length: Varies significantly by engine. Common lengths are around 104-106 inches for Cummins ISX15.
• Rib Count: 8-rib (common for heavy-duty applications).
• OEM Belt PN (Cummins ISX15): 4089020 (verify with your specific engine serial number)
• Aftermarket Cross-references (Cummins ISX15 - verify length and rib count):
  • Gates K081050 (8-rib, ~105 inches)
  • Dayco 5081050 (8-rib, ~105 inches)
  • Continental Elite 4081050 (8-rib, ~105 inches)
• Auto-Tensioner PN (Cummins ISX15): 3680237 (verify with your specific engine serial number)
• Idler Pulley PN (Cummins ISX15): 3680238 (verify with your specific engine serial number)

Belt Routing (Cummins ISX15 Engine)

Always take a clear photograph of your serpentine belt routing before you begin removal. This will serve as an invaluable reference during reinstallation.

The serpentine belt on a 2014 Kenworth W900 with a Cummins ISX15 engine typically follows a complex path to drive multiple accessories. While exact routing can vary slightly based on specific accessory configurations, a common path looks like this:

1. Crankshaft Pulley: The belt originates from the main crankshaft pulley, which powers all other accessories.
2. A/C Compressor: From the crankshaft, the belt usually travels up to the A/C compressor pulley.
3. Idler Pulley (lower): After the A/C compressor, the belt may pass around a lower idler pulley, which helps guide the belt and maintain tension.
4. Alternator: The belt then typically wraps around the alternator pulley, providing power for the electrical system and battery charging.
5. Power Steering Pump: Next, the belt often routes to the power steering pump pulley, assisting in steering.
6. Water Pump: From the power steering pump, the belt usually goes to the water pump pulley, circulating coolant through the engine.
7. Idler Pulley (upper): Another idler pulley, often positioned higher, might be encountered to properly route the belt.
8. Automatic Tensioner: Finally, the belt will wrap around the automatic tensioner pulley. The tensioner applies consistent pressure to the belt, ensuring proper grip and preventing slippage.

Remember, this is a general routing description. Your specific engine could have variations. The photograph you take beforehand will be your most reliable guide.

How to Replace the Serpentine Belt

Replacing a serpentine belt on a heavy-duty truck like the Kenworth W900 requires patience and the right tools. Here's a general procedure:

1. Safety First: Ensure the engine is off and cool. Disconnect the negative battery terminal to prevent accidental starting.
2. Locate the Tensioner: Identify the automatic belt tensioner. It will have a square opening, typically 3/8-inch or 1/2-inch, designed to accept a breaker bar or a specialized serpentine belt tool.
3. Relieve Tension: Insert the appropriate-sized breaker bar or serpentine belt tool into the tensioner's square opening. Rotate the tensioner to relieve tension on the belt. This will allow you to easily slip the belt off the pulleys.
4. Remove Old Belt: While maintaining pressure on the tensioner, carefully remove the old belt from one or more pulleys until it can be completely removed from the engine compartment.
5. Route New Belt: Using your photograph as a guide, meticulously route the new serpentine belt around all the pulleys, leaving the tensioner pulley for last or one of the last pulleys to engage.
6. Engage Tensioner and Verify: Once the belt is correctly routed on all pulleys except the tensioner, use the breaker bar/tool to once again relieve tension on the tensioner. Slip the belt over the tensioner pulley. Slowly release the tensioner, ensuring the belt seats properly in all pulley grooves.
7. Double-Check: Visually inspect all pulleys to confirm the belt is correctly seated and aligned. Rotate the crankshaft by hand (if possible and safe to do so) a full rotation and re-check.
8. Reconnect Battery and Test: Reconnect the negative battery terminal. Start the engine and listen for any abnormal noises (squealing, chirping). Observe the belt